Google has digitized more than 5 million books in a project that also enables users to track changes in scholarly attention to particular topics. I did a few searches and came up with these results. They obviously do not mean much and are only useful in knowing what scholars paid more attention to at any given time.

Like this:

The Economist reports a scientific finding that links nutrition and disease burden to human intelligence. The findings add to the development debate by suggesting that disease burden, through its effect on brain development, is a significant predictor of a country’s average intelligence level and that this in turn may explain endemic underdevelopment within the tropics. The questionable inferences from the research findings aside (see the comments section of the Economist article) my two cents on this is that it doesn’t matter. Firstly, a low average does not preclude outliers on the right hand side. And secondly, a country only needs so many Einsteins (Read Debraj and others on the impact of tertiary education on development). Plus after reading Bernstein I can bet that the average Sri Lankan or Chadian is still smarter than the average Renaissance man, despite the latter’s spectacular achievements.

What really matters for economic development are Institutions and the rule of law. These can help countries survive even not so bright leaders – Bush’s America is a good example here. Of course the bigger problem is that it might be the case that you need a high national average intelligence to maintain self-reinforcing institutions that promote development. But even this would be a tough sell given the high variance in institutional capacity across different countries with different disease burdens (contrast Cuba with some of the poorer and sicker but higher ranked countries for instance).

The causal link between poor nutrition, a high disease burden and cognitive development probably exists. But I don’t think that the impact is large enough to explain underdevelopment in the global South. Just until 150 years ago there was not much variation in the average life expectancy across the different regions of the world despite the disparate development levels.

update: Here is a paper that documents the secular increase in IQ levels in Sudan. In light of the above article, poor countries need not worry. It appears that modernization will take care of their low average IQ worries.

BARCELONA (Reuters) - Spain mounted a sweeping anti-terror operation on Friday after a suspected Islamist militant drove a van into crowds in Barcelona, killing 13 people before fleeing, in what police suspect was one of multiple planned attacks.

WASHINGTON (Reuters) - The United States and Japan will step up their defense cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

CARACAS (Reuters) - Venezuela will hunt down and jail leaders of violent protests that have rocked the country since April, its new top prosecutor said on Thursday, a day before a hate crimes law was expected to be approved despite fears that it will be used to crush dissent.